diff --git a/interop/interop_test.sh b/interop/interop_test.sh
index 99e12c3c3..65e12a16b 100755
--- a/interop/interop_test.sh
+++ b/interop/interop_test.sh
@@ -45,6 +45,20 @@ pass () {
     echo "$(tput setaf 2) $(date): $1 $(tput sgr 0)"
 }
 
+withTimeout () {
+    timer=$1
+    shift
+
+    # Run command in the background.
+    cmd=$(printf '%q ' "$@")
+    eval "$cmd" &
+    wpid=$!
+    # Kill after 20 seconds.
+    sleep $timer && kill $wpid &
+    # Wait for the background thread.
+    wait $wpid
+}
+
 # Don't run some tests that need a special environment:
 #  "google_default_credentials"
 #  "compute_engine_channel_credentials"
@@ -70,6 +84,8 @@ CASES=(
   "custom_metadata"
   "unimplemented_method"
   "unimplemented_service"
+  "orca_per_rpc"
+  "orca_oob"
 )
 
 # Build server
@@ -96,7 +112,12 @@ for case in ${CASES[@]}; do
     echo "$(tput setaf 4) $(date): testing: ${case} $(tput sgr 0)"
 
     CLIENT_LOG="$(mktemp)"
-    if ! GRPC_GO_LOG_SEVERITY_LEVEL=info timeout 20 go run ./interop/client --use_tls --server_host_override=foo.test.google.fr --use_test_ca --test_case="${case}" &> $CLIENT_LOG; then
+    if ! GRPC_GO_LOG_SEVERITY_LEVEL=info withTimeout 20 go run ./interop/client \
+         --use_tls \
+         --server_host_override=foo.test.google.fr \
+         --use_test_ca --test_case="${case}" \
+         --service_config_json='{ "loadBalancingConfig": [{ "test_backend_metrics_load_balancer": {} }]}' \
+       &> $CLIENT_LOG; then
         fail "FAIL: test case ${case}
         got server log:
         $(cat $SERVER_LOG)
diff --git a/interop/test_utils.go b/interop/test_utils.go
index 0057c0712..29916876e 100644
--- a/interop/test_utils.go
+++ b/interop/test_utils.go
@@ -30,6 +30,7 @@ import (
 	"io"
 	"os"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/golang/protobuf/proto"
@@ -779,6 +780,7 @@ func DoSoakTest(tc testgrpc.TestServiceClient, serverAddr string, dopts []grpc.D
 type testServer struct {
 	testgrpc.UnimplementedTestServiceServer
 
+	orcaMu          sync.Mutex
 	metricsRecorder orca.ServerMetricsRecorder
 }
 
@@ -842,11 +844,6 @@ func (s *testServer) UnaryCall(ctx context.Context, in *testpb.SimpleRequest) (*
 		// recorder in the context, if present.
 		setORCAMetrics(r, orcaData)
 	}
-	if r, orcaData := s.metricsRecorder, in.GetOrcaOobReport(); r != nil && orcaData != nil {
-		// Transfer the request's OOB ORCA data to the server metrics recorder
-		// in the server, if present.
-		setORCAMetrics(r, orcaData)
-	}
 	return &testpb.SimpleResponse{
 		Payload: pl,
 	}, nil
@@ -912,6 +909,7 @@ func (s *testServer) FullDuplexCall(stream testgrpc.TestService_FullDuplexCallSe
 			stream.SetTrailer(trailer)
 		}
 	}
+	hasORCALock := false
 	for {
 		in, err := stream.Recv()
 		if err == io.EOF {
@@ -929,6 +927,11 @@ func (s *testServer) FullDuplexCall(stream testgrpc.TestService_FullDuplexCallSe
 		if r, orcaData := s.metricsRecorder, in.GetOrcaOobReport(); r != nil && orcaData != nil {
 			// Transfer the request's OOB ORCA data to the server metrics recorder
 			// in the server, if present.
+			if !hasORCALock {
+				s.orcaMu.Lock()
+				defer s.orcaMu.Unlock()
+				hasORCALock = true
+			}
 			setORCAMetrics(r, orcaData)
 		}
 
@@ -1036,14 +1039,12 @@ func DoORCAOOBTest(tc testgrpc.TestServiceClient) {
 		logger.Fatalf("/TestService/FullDuplexCall received error receiving: %v", err)
 	}
 
-	ctx2, cancel := context.WithTimeout(ctx, 5*time.Second)
-	defer cancel()
 	want := &v3orcapb.OrcaLoadReport{
 		CpuUtilization: 0.8210,
 		MemUtilization: 0.5847,
 		Utilization:    map[string]float64{"util": 0.30499},
 	}
-	checkORCAMetrics(ctx2, tc, want)
+	checkORCAMetrics(ctx, tc, want)
 
 	err = stream.Send(&testpb.StreamingOutputCallRequest{
 		OrcaOobReport: &testpb.TestOrcaReport{
@@ -1061,14 +1062,12 @@ func DoORCAOOBTest(tc testgrpc.TestServiceClient) {
 		logger.Fatalf("/TestService/FullDuplexCall received error receiving: %v", err)
 	}
 
-	ctx3, cancel := context.WithTimeout(ctx, 5*time.Second)
-	defer cancel()
 	want = &v3orcapb.OrcaLoadReport{
 		CpuUtilization: 0.29309,
 		MemUtilization: 0.2,
 		Utilization:    map[string]float64{"util": 0.2039},
 	}
-	checkORCAMetrics(ctx3, tc, want)
+	checkORCAMetrics(ctx, tc, want)
 }
 
 func checkORCAMetrics(ctx context.Context, tc testgrpc.TestServiceClient, want *v3orcapb.OrcaLoadReport) {